As described in a copending application filed on an even date herewith by John T. Apostolos entitled Orientation-Independent Antenna (ORIAN), assigned to the assignee hereof and incorporated herein by reference, a pair of crossed vertical loops in combination with a horizontal loop may be phased to provide circular polarization in a hemisphere surrounding the antenna such that signals are robustly received regardless of their polarization or angle of arrival. The antenna described in this copending Application is a free standing antenna used, inter alia, on robots or robotic vehicles so that regardless of the angle of arrival of the incoming signal or its polarization the signals will be robustly received. This means that relatively low power signals as from satellites can be received by this orientation-independent antenna.
In one embodiment of the antenna, this antenna is in the form of a cube with various triangular shaped antenna elements disposed on the surface of the cube. Through a relatively sophisticated phasing network, the vertical crossed loops associated with the antenna are fed 90 degrees out of phase, as is a horizontal loop which is 90 degrees out of phase with both of the crossed vertical loops.
Stepped phasing is also utilized for the various legs of the loops of the antenna. Note that the net result is that the crossed vertical loops provide circular polarization at the azimuth but require a horizontal polarization component fill close to the zenith or horizon.
While the orientation-independent antenna described above is useful in many applications, there is a requirement for a UHF antenna that is miniaturized and broad banded to be mounted on the top of a car, vehicle or any other platform such a turret. The broad banded nature of such an antenna is to eliminate the need for a number of specialized antennas on the vehicle. Also what is required is a low profile antenna that is both efficient and has an orientation-independent characteristic.
The orientation-independent characteristic permits signals arriving at any angle of arrival above the horizon and any polarization to be received. As will be appreciated, polarization can vary from linear polarization to circular polarization or anywhere in between including elliptical polarization.
If one could somehow adapt the cubic orientation-independent antenna as a low profile antenna for use on vehicles, robust communications could be achieved over a wide bandwidth so as eliminate the forest of antennas that normally graces the vehicles or platforms.
Of course, not having a whip antenna would eliminate the snagging of the antenna in branches, trees and other obstacles and, for instance in the case of an aircraft in and about a naval vessel, the aircraft could be free of the vertical forest of antennas that usually is present on warships.